The invention relates to a process for the production of a material for sealing and healing wounds which comprises the even application of a suspension to a collagen carrier.
A material for sealing and healing wounds which comprises a collagen carrier, coated with a fibrin component, a thrombin component, such as calcium ions, protease inhibitors or heparin antagonists, is known from U.S. Pat. No. 4,453,939.
To prepare this material, the individual components or additives are suspended in an organic solvent, e.g. ethanol, and subsequently applied to a collagen carrier, e.g. by means of spraying.
In doing this, several problems arise, because the suspension to be applied is difficult to handle. For example, the nozzles usually used for these purposes clog immediately. Lignial air nozzles permit the use of a larger diameter, but even in this case, only nozzles with the largest diameter available allow working with a sufficient lack of trouble. However these nozzles show a fatal disadvantage. The indistinct definition of the exiting stream does not apply an even layer of the suspension but creates a trapezoidal coating profile on the collagen carrier. This leads to considerable losses of collagen carrier and valuable suspension at the edges.
A device for applying a liquid film to a fabric web according to the pouring-out principle is known from EP-A 472 050. By means of individual partitions for liquid which are located directly next to one another, this device achieves a forced distribution of the liquid from a feed opening to a number of outflow openings. The liquid is distributed in the form of a family tree, i.e step by step from one opening to two, four, eight, sixteen etc, outflow openings. This device is not suitable for the even distribution of a suspension consisting of fibrinogen and thrombin components, as the several divisions of the liquid stream cause conglutination and clogging of the partitions by the suspension; furthermore, this conglutination and clogging occurs to a greater extent then when nozzles are used.